This invention relates generally to armor plate and more particularly to light-weight multiple-impact defeating armor plate.
Broadly speaking, there are two main classes of light-weight armor plates: ceramic and metallic. The ceramic armor plates are the more efficient class from the standpoint of defeating armor piercing projectiles at the lowest weight per square foot of surface area (areal density). The ceramic armor sections are generally mounted on a tough support layer such as glass reinforced plastics. Boron carbide, silicon carbide and alumina are ceramics which are commonly used in armor plating.
Ceramic plates have the serious drawback of being unable to sustain and defeat multiple hits by armor piercing projectiles. Because relatively large sections of ceramic material must be used to stop these projectiles and because these sections shatter completely when hit by a projectile, the ceramic armor can not defeat a second projectile impacting close to the preceding impact. Moreover, sympathic shattering of adjacent ceramic sections usually occurs, still further increasing the danger of penetration by multiple rounds. Furthermore, ceramic armors are fragile and susceptible to catastrophic damage through normal handling.
In addition, ceramic armors are difficult and costly to manufacture, due to the very high manufacturing temperatures. Their processing may also be time consuming due to very slow cooling which is necessary to avoid cracking of the ceramic armor as its atomic structure transforms at the ceramic's inversion temperatures.
The other class of light-weight armor plate is metallic. Although this class possesses excellent ability to defeat multiple, closely spaced impacts of armor piercing projectiles, it is far heavier than desired, difficult to fabricate into intricate contours and difficult to repair in the field. Furthermore, its weight precludes its extensive use in such light-weight mobile weapons systems as helicopters and small water craft. In this regard, it should be noted that metallic armor of the same weight as ceramic armor is incapable of defeating armor piercing rounds.
An improved armor plate was disclosed in patent application Ser. No. 78,337 filed on Sept. 2, 1970, now abandoned, by David Goldstein and William J. Buehler. That armor plate was formed of an array of tiles composed of particles of a hard material which is a carbide, boride, nitride, silicide or mixture thereof dispersed in a matrix of tough, crack resistant iron based alloy, the tiles being attached to a support layer of tough, fragment resistant material. That armor was light weight, easy to manufacture and repair, and capable of stopping multiple, closely spaced impacts of armor piercing projectiles. However, it is desirable to find armor plating which has still better stopping capability while retaining the advantages of light weight and ease of manufacture and repair.